ATTENTION TO WITHIN-OBJECT AND BETWEEN-OBJECT SPATIAL REPRESENTATIONS - MULTIPLE SITES FOR VISUAL SELECTION

Our ability both to recognise visually presented objects and to interact with them appropriately depends upon detailed interaction between visual attentional and visual recognition systems. We report data from two neuropsychological cases indicating that the allocation of attention in vision is determined by at least two forms of spatial representation (within-object and between-object spatial coding). In both cases there was unilateral neglect of one side of visual displays if items in the displays were coded as parts of a single perceptual object, and neglect of the opposite side if items were coded as separate perceptual objects. In addition, attentional cueing effects to either the left or right side were specific to the form of representation involved. These cases demonstrate that there is parallel coding of visual displays into within- and between-object spatial representations. Further, visual selection operates independently on the two forms of visual representation. The data support an argument for the existence of multiple sites of selection in vision.